使用LayoutInflator（）时出现空指针异常？

Question

I'm using the LayoutInflator to try and get the user's text to display in a TableLayout (Which is a child of a scrollView ) But so far, it just keeps throwing the Null Pointer Exception. All the IDs are working fine, I tried cleaning the project to see if that would help but to no avail, can anyone help me out?

By the way, it tells me the error is in 2 places, reminderListTextView.setText(text); and in inflate("test");

Code:

public class MainActivity extends ActionBarActivity {

    private TableLayout reminderTableScrollView;

    // TextView and Button added
    EditText reminderEditText;

    Button addReminderButton;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        reminderTableScrollView = (TableLayout) findViewById(R.id.reminderTableScrollView);

        reminderEditText = (EditText) findViewById(R.id.reminderEditText);

        addReminderButton = (Button) findViewById(R.id.enterButton);
        addReminderButton.setOnClickListener(reminderClickListener);
    }

    private OnClickListener reminderClickListener = new Button.OnClickListener() {

        @Override
        public void onClick(View v) {
            if (reminderEditText.getText().toString() == null || reminderEditText.getText().toString() == "") {
                Toast.makeText(getApplicationContext(), "Enter reminder", Toast.LENGTH_SHORT).show();
            } else {
                inflate("Test");
                reminderEditText.setText("");
            }
        }
    };

    public void inflate(String text) {
        LayoutInflater inflator = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View reminder = inflator.inflate(R.layout.reminder_layout, null);

        TextView reminderListTextView = (TextView) findViewById(R.id.reminderListTextView);
        reminderListTextView.setText(text);

        reminderTableScrollView.addView(reminder);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.menuAdd) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

Answer 1

It's actually in just one place that you get the exception : reminderListTextView.setText(text); , the 2 lines are the trace to tell you that you get the error at reminderListTextView.setText(text); when inflate("test"); is called.

Try reminder.findViewById(...); , you need to use the view in which you inflated the layout to be able to retrieve elements from it.

Answer 2

Try changing your inflate method to this:

public void inflate(String text) {
    LayoutInflater inflator = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    View reminder = inflator.inflate(R.layout.reminder_layout, null);

    TextView reminderListTextView = (TextView)reminder.findViewById(R.id.reminderListTextView);
    reminderListTextView.setText(text);

    reminderTableScrollView.addView(reminder);
}

Without seeing your reminder_layout, I'm not certain, but I'm guessing the view with id reminderListTextView is in your reminder_layout.xml and not your activity_main.xml